614,162. Pneumatic tyres. GENERAL TIRE & RUBBER CO. June 8, 1945, No. 14550. Convention date, Sept. 22, 1939. [Class 144 (i)] In a method of building tyre-covers by the flat-band process, the innermost plies of tyre material are laid on the building-drum with overhanging edges which are then folded radially outwards to provide edge folds, superposed plies are then assembled and their edges folded radially inwards to enclose the folded edges of the underlying material, the folding - devices operating simultaneously throughout the circumference of the material. Before folding the underlying ply, the tyre beads with attached flippers, are applied to the overhanging material at the sides of the drum, the consolidation of the successive plies and the tread being effected by helical-spring rings and a pair of stitcher wheels having a wiping action transversely of the drum. The variable-speed rotation of the drum, and the actuation of the associated operating-devices, are effected by electricallycontrolled means arranged to function in continuous sequence. The machine for carrying out the process comprises generally a fabric-supply equipment E; a building-drum D; movable and fixed carriages C, M respectively, each fitted with bead setting and pressing devices H; devices F for folding the edges of the ply material around the beads; primary smoothers or pressers P movable over major portions of the drum; devices S for compacting and smoothing the material at the extreme end zones only of the drum; and a pair of axially-movable stitcher-wheels W. Building-drum. The drum is of the (known) collapsable type and is mounted on one end of a shaft 69, Fig. 8, and a surrounding sleeve 70 which normally rotate together. To collapse the drum for removal of the built-up tyre, the sleeve is arrested by means of an electromagnetically-operated brake. As shown, the width of the drum may be varied, for different-sized tyres, by axial displacement of rim-portions 627, 628 over the drum-body 629, the gap between the parts 627, 628 being closed by a thin band 630. Servicer. Sets of stock-rolls 606, Fig. 39, and liner take-up rolls 607, are carried on endless bands 605 mounted on rollers 604 on a turret 602. Adjustment of the bands 604 permits successive rolls of each set to be aligned with an apron 609 leading to the building-drum. When one set of rolls has been used, the turret is swung to align the second set with the drum, the first set being replenished without disturbing the continuous operation of the machine. Below the turret, the tread-rubber stock is fed from a spool 611 over a roller 615 movable to and from the drum. The rubber 614 is pressed on to the ply material on the drum, and the liner strip 613 led to a take-up roll 616. The chafer-strip stock 618 is fed from a pair of spools 617 over festooning-rollers 620, the liner 619 being led over rollers 621 to a take-up roll 622. The tread-stock T, in lengths to form one annulus, is fed to the drum on a conveyer consisting of closely spaced rollers 623. Carriage shifting. The carriage C is moved to and from the building-drum by rods 87 pivoted to cranks 84 on a cross-shaft carrying a gear forming part of a timed solenoid-clutch. Bead setting. The bead rings Band flipperstrips 801, Fig.' 43, are assembled on spring- fingers 103 carried by the flange 101 of a hollow sleeve 100 movable to and from the building- drum along a shaft 104 aligned with the drum shaft. Rings 111, axially movable over the periphery of the flange 101 follow the beads up to the drum and are then forcibly pressed to consolidate the beads by a rack-operated wedge-toothed spider 117. The bead-holding and setting devices H are moved by rods 151, 152, Fig. 10, connected at one end to the flanges of sleeves 109 slidable on the hollow sleeve 100 and at their other ends to'crankoperated toggles 158, 159. Turn-buckles 156 are provided in the rods to adjust the limitpositions of the bead-holders. Shoulder smoothers. As shown in Figs. 8. and 10, the devices for operating on the shoulder portions of the tyre material each comprise a helical-spring ring 200 which is normally disposed around the pressure-member 111 of the bead-setter and carried by a series of actuator-arms 201 pivoted on the flange 110 of the sleeve 109. The springs 200, which are normally in tension, are further expanded ,as they ride from the bead-presser rings 111 over the building - drum to exert consolidating pressure on the beads and flippers. Fabric folders. The devices F for folding the edge portions of the tyre material into position for consolidation by the smoothers and stitchers each comprise a disc 300, Fig. 11, slidable on the shaft or sleeve carrying the drum. The ends of the drum are apertured to receive the discs in their inoperative position. The actual folding-members 305 are slidable in slots in the discs and are actuated by links 307 pivoted to a sleeve 308 slidable on the drum mountings. The reciprocations of the discs and sleeve are effected by cam-controlled mechanisms which include solenoid-controlled clutches. Primary pressers. The smoothers or pressers P for compacting the tyre material on the drum comprise helical-spring rings 400 supported on arms 401, Fig. 8, which are pivoted intermediate their ends on bracket-extensions of rings 404. The outer ends of the arms 401 are fitted with rollers 417 which, in the withdrawing movement of the presser-rings, engage a fixed conical drum 414 to hold the rings sufficiently expanded to clear the bead-setting devices B. The rings are held distended in their movement towards the building-drum by latches 418 on the arms 401 engaging rings 419 which are slidable on the rings 404, the latches being withdrawn as the presser-rings reach the drum. Stitchers. A pair of stitcher-wheels W are mounted on a right-and-left threaded spindle 503, Figs. 1 and 30, the ends of which are journalled in arms 504 which are swung on fixed pivots 505 to bring the stitchers into frictional contact with the material on the drum to perform their wiping action. The stitchers are normally positioned below and clear of the drum and are raised into operative position by weights 521, 528 connected by chains 516 to selected points on the arms 504. The upper weights 528 are adapted to engage stop-shoulders so as to become inoperative when the stitchers are traversing the relativelythinner portions of the tyre material on the drum. To return the stitchers to their initial position on the spindle 503, they are lowered on to driven rubber &c. roller 533. Operation. A multiple ply 802, 803, Fig. 41, of cord material is drawn from one or more of the stock rolls and applied to the building- drum D which is given one revolution, at slow speed, by the actuation of a foot-switch. The primary pressers 400 are then actuated to consolidate the material and fold the edges over the ends 205 of the drum. The beads B and the flippers 801, Fig. 43, are then assembled and pressed into position by the carrier-rings 111 and presser-rings 200. The edge flaps of the underplies are then lapped over the beads by the axial and radial movements of the segmental folders 306. Finally, the additional plies, chafer strips, and tread stock are applied and consolidated by the pressers 400 and stitchers.